UNIVERSITY  OF  CALIFORNIA   Pf  PLICATIONS 

COLLEGE  OF  AGRICULTURE 
AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


?The  Determination  of  Availability  of  JNitro 

genous  Fertilizers  in  Various  California 

Soil  Types  by  Their  Nitrifiability" 


BY 

C.  B.  LIPMAN  and  P.  S.  BURGESS 


BULLETIN  No.  260 

Berkeley,  Cal.,  October,  1915 


California 
State  Printing  Office 
19  15 


Benjamin  Ide  Witeeler,  President  of  the  University. 

EXPERIMENT   STATION   STAFF 

HEADS   OF    DIVISIONS 

Thomas  Forsyth  Hunt,  Director. 

Eugene  W.  Hilgard,  Agricultural  Chemistry   (Emeritus). 

Edward  J.  Wickson,  Horticulture  (Emeritus). 

Herbert  J.  Webber,  Director  Citrus  Experiment  Station;  Plant  Breeding. 

Hubert  E.  Van  Norman,  Vice-Director  ;  Dairy  Management. 

William  A.  Setchell,  Botany. 

Myer  E.  Jaffa,  Nutrition. 

Robert  H.  Loughridge,  Soil  Chemistry  and  Physics   (Emeritus). 

Charles  W.  Woodwortii,  Entomology. 

Ralph  E.  Smith,  Plant  Pathology. 

J.  Eliot  Coit,  Citriculture. 

John  W.  Gilmore,  Agronomy. 

Charles  F.  Shaw,  Soil  Technology. 

John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 

Frederic  T.  Bioletti,  Viticulture  and  Enology. 

Warren  T.  Clarke,  Agricultural  Extension. 

John  S.  Burd,  Agricultural  Chemistry. 

Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 

Clarence  M.  Haring,  Veterinary  Science  and  Bacteriology. 

Ernest  B.  Babcock,  Genetics. 

Gordon  H.  True,  Animal  Husbandry. 

James  T.  Barrett,  Plant  Pathology. 

Fritz  W.  Woll,  Animal  Nutrition. 

A.  V.  Stubenrauch,  Pomology. 

Walter  Mulford,  Forestry. 

W.  P.  Kelley,  Agricultural  Chemistry. 

H.  J.  Quayle,  Entomology. 

Elwood  Mead,  Rural   Institutions. 

J.  B.  Davidson,  Agricultural  Engineering. 

H.  S.  Reed,  Plant  Physiology. 

William  G.  Hummell,  Agricultural  Education. 

Leon  M.  Davis,  Dairy  Industry. 

John  E.  Dougherty,  Poultry  Husbandry. 

Frank  Adams,  Irrigation  Practice. 

David  N.  Morgan,  Assistant  to  the  Director. 

Mrs.  D.  L.  Bunnell,  Librarian. 

DIVISION    OF    SOIL    CHEMISTRY    AND    BACTERIOLOGY 

C.  B.  Lipman  W.  F.  Gericke 

L.  T.  Sharp  M.  A.  Klein 

L.  E.  Bailey 


THE  DETERMINATION  OF  AVAILABILITY  OF  NITRO- 
GENOUS FERTILIZERS  IN  VARIOUS  CALIFORNIA 
SOIL  TYPES  BY  THEIR  NITRIFIABILITY 

By  C.  B.  Lipman  and  P.  S.  Burgess. 

In  the  broad  sense,  a  plant  food  element  or  compound  is  ' '  available ' ' 
when  it  is  in  such  a  form  as  to  be  soluble  in  the  soil  water  in  the  first 
place  and  capable  of  being  built  into  plant  substance  without  harmful 
effects  in  the  second  place.  The  second  of  course  implies  the  first,  but 
the  opposite  is  not  necessarily  true.  Experiments  have  shown,  more- 
over, that  plants  are  not  alike  in  their  ability  to  use  soil-water  soluble 
nitrogen  compounds ;  some  of  them  must  have  one  form,  others  another 
form,  and  still  others  are  indifferent  to  the  form  and  use  one  as  well  as 
another.  Technically  speaking  therefore,  it  is  only  possible  to  obtain 
accurate  data  on  the  relative  availability  of  different  forms  of  nitrogen 
through  the  empiricism  of  extensive  tests  with  every  plant.  Practically, 
however,  this  would  appear  to  be  quite  superfluous  since  under  soil 
conditions  in  the  field  as  they  should  be  maintained  for  normal  crop 
production,  relatively  little  nitrogen  is  present  in  truly  "available" 
forms  other  than  nitrates.  For  plant  growth  purposes  therefore  we 
are  reasonably  safe  in  assuming  that  the  problem  of  nitrogen  nutri- 
tion is  chiefly  one  of  supplying  to  the  root  zone  enough  nitrate  at 
different  parts  of  the  life  of  the  plant  to  insure  normal  growth.  If  this 
is  assumed  to  be  the  case,  and  we  feel  justified  in  that  assumption,  then 
obviously  the  question  of  the  relative  availabilities  of  different  nitro- 
genous fertilizers  resolves  itself  into  one  of  the  rate,  and  the  complete- 
ness of  their  transformation  into  nitrate ;  perhaps  also  in  a  minor  way 
it  is  one  of  dissemination  of  such  nitrate  over  the  soil's  internal  surface. 

With  the  foregoing  ideas  as  a  basis  we  have  attempted  first  to  compare 
under  like  and  controlled  conditions  as  to  moisture,  temperature  and 
aeration  the  nitrifiability  or  the  rate  and  completeness  of  nitrogen  trans- 
formation into  nitrate  in  a  variety  of  nitrogenous  fertilizers  in  any  one 
soil,  and  second,  to  compare  them  in  different  soils,  knowing  as  we  do 
how  soils  differ  in  the  direction  indicated.  We  have  indeed  gone  to 
the  extent  of  determining  besides  nitrifiability  the  ammonifiability  also, 
or  the  rate  and  completeness  of  nitrogen  transformation  in  the  same 
fertilizers  into  ammonia.  Since,  however,  ammonia  has  a  very  epheme- 
ral existence  in  soils  and  since  it  is  so  readily  transformed  into  nitrates 
under  normal  conditions,  we  shall  only  give  consideration  here  to  the 
nitrifiability  of  the  forms  of  nitrogen  with  which  we  have  experimented. 

Crop-Producing    Power   of   a    Soil    as    Related    to    its    Nitrifying    Power. 

Before  making  a  statement  with  regard  to  the  more  detailed  nature 
of  our  experiments,  we  feel  constrained  to  give  further  justification  for 
cur  attitude  towards  the  use  of  nitrifiability  of  a  nitrogenous  material 


108  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

as  a  criterion  of  its  availability  to  plants.  A  number  of  investigators 
in  Europe  and  notably  in  recent  years  Vogel,  have  clearly  demonstrated 
the  relationship  between  the  nitrifying  power  of  a  soil  and  its  crop- 
producing  power.  It  was  found  by  Vogel  for  example,  that  in  two 
experimental  plots  of  the  same  soil  and  adjacent  to  each  other,  the  one 
which  had  a  nitrifying  power  in  the  laboratory,  (so  far  as  horn  meal 
was  concerned,)  which  was  50%  higher  than  that  of  the  other,  gave  an 
increase  in  beet  yield  of  about  20%  over  the  last  mentioned  plot.  Simi- 
larly also  when  cabbage  was  grown  the  plot  with  the  higher  nitrifying 
power  as  above  described  surpassed  the  other  in  yield  by  about  30%. 
Similar  observations  were  made  also  in  this  country  by  Lyon  and  his 
co-workers  at  Cornell  and  also  by  the  authors  whose  findings  in  that 
direction  will  be  published  later.  Despite  the  fact,  therefore,  that  the 
laboratory  tests  of  a  soil's  nitrifying  power  are  carried  out  with 
materials  and  physical  conditions  quite  unlike,  in  nature  or  amount, 
those  which  obtain  in  the  field,  experiment  appears  to  have  established 
clearly  the  existence  of  a  relationship  between  the  two  which  can  not  be 
seriously  doubted.  To  be  thoroughly  conservative  in  the  matter,  how- 
ever, we  need  but  regard  for  the  purposes  of  the  work  described  in  this 
bulletin,  the  laboratory  figures  as  being  only  of  relative  value  and  not 
as  of  absolute  significance.  In  other  words,  we  need  only  assume  that 
the  relationship  which  obtains  in  a  given  soil  under  laboratory  con- 
ditions with  a  variety  of  nitrogenous  fertilizers  will  also  obtain  in  a 
similar  manner  under  field  conditions  and  not  that  the  amounts  of 
nitrate  produced  would  be  asbolutely  the  same.  Similarly,  with  dif- 
ferent soils,  one  and  the  same  fertilizer  should  yield  corresponding 
relationships.  Taking  together,  therefore  the  ideas  presented  in  this 
paragraph,  we  feel  that  we  are  conservative  in  the  belief  that  avail- 
ability of  nitrogen  in  nitrogenous  fertilizers  as  measured  by  their 
nitrifiability  is  of  practical  value  in  farm  operations,  since  a  strong 
relationship  obtains  between  the  crop  producing  power  of  a  soil  and  its 
nitrifying  power;  also  because  for  practical  purposes,  it  is  not  so 
important  to  obtain  the  absolute  figures  for  the  nitrifiability  of  a  given 
nitrogenous  fertilizer  as  to  obtain  the  value  for  its  nitrifiability  as  com- 
pared to  those  of  other  nitrogenous  fertilizers. 

Statement    of    the    Experiments    with    Methods    Employed. 

The  basis  upon  which  our  experiments  were  carried  out  was  the 
study  of  the  amount  of  nitrate  produced  in  one  month  at  a  constant 
temperature  in  a  warm  chamber  of  82°  F.  to  86°  F.  from  a  given 
amount  of  fertilizer  material  thoroughly  mixed  with  soil.  In  order  to 
accomplish  this  object  100  gram  portions  of  soil  were  employed  and 
except  as  otherwise  stated  in  the  tables  below,  one  gram  of  the  fertilizer 
was  thoroughly  mixed  with  the  soil  in  the  dry  state.     No  attempt  was 


[Bulletin  260] 


NITROGENOUS    FERTILIZERS. 


109 


made  to  insure  the  use  of  equal  quantities  of  nitrogen  in  the  case  of  all 
fertilizers  tested  since  owing  to  the  great  diversity  in  the  amounts  of 
nitrogen  contained  in  them,  there  was  great  danger  of  introducing 
physical  factors  of  great  interference  into  the  tests.  After  the  fertilizer 
and  soil  were  thoroughly  mixed  in  the  plain  glass  tumbler  in  which 
they  were  to  be  incubated,  enough  distilled  water  was  added  to  give  the 
soil  optimum  moisture  conditions.  The  tumbler  was  then  covered  with 
a  glass  plate  to  prevent  too  great  a  loss  of  moisture  by  evaporation 
and  was  incubated  as  above  explained.  From  time  to  time  enough 
water  was  added  to  the  tumblers  to  keep  the  moisture  conditions  as 
nearly  as  possible  constant  in  the  cultures. 

Twenty-nine  types  of  soil,  representing  a  number  of  the  important 
soil  regions  of  California,  were  employed  with  every  fertilizer  except 
as  otherwise  stated.  The  physical  nature  and  derivation  of  the  soils 
are  given  in  the  following  table : 

TABLE  I. 

Description  of  Soils   Employed  in   the  Experiments. 


Number 

Derivation 

General  characteristics 

Total  N 
per  cent 

1 

Anaheim,    Walnut    orchard  -_  

Fertile  sand   _    

C6 

2 

Oakley,    peach   orchard      _                  

Fine  blow   sand    _ 

03 

3 

Covina,   citrus  orchard 

Fertile  sand  _  __.  ___  

.06 

4 
5 
6 

7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20^ 
21 
22 
23 
24 
25 
26 
27 
28 
29 

Claremont,   Pomona  College  campus 

Watsonville,   strawberry  patch    

Rich  loam  __  __ 

.13 

Rich    clay   loam__ 

17 

Berkeley,   University  campus _    _ 

Fertile  clay   adobe 

Fertile   clay  loam  _  

11 

Davis,  grain  field,  University  Farm 

Holtville,   grain  and  alfalfa  land 

Manteca,  vineyard 

.08 

Recently  reclaimed  silty  clay 

Coarse  sand 

.03 
C4 

Selma,    vineyard 

"White    ash"    sand-  __      

.03 

Selma,    peach   orchard 

"Humus  poor"  sand  __    _. 

.02 

El  Cajon,  hav  field 

Heavy   clay 

.04 

El  Cajon,  hay  field 

Infertile  sand 

.03 

Willows,   grain  field  .  _ 

Heavy  clay  

.05 

Bayliss   Camp,    alfalfa  field 

Alluvial  silt  loam 

.09 

Olinda    _. 

Silt    loam 

.15 

Paradise 

Humus    silt    loam 

.11 

Napa,  grain  field __    __  .  . 

Gravelly   loam 

.12 

Craftcn,  citrus  orchard 

Clay   loam 

.05 

San  Fernando,  citrus  orchard.  

Fertile,    sandy  loam... 

.08 

Alluvial  silt  loam__ 

.29 

Castroville,  sugar  beet  field 

Heavy  silt   loam 

.05 

Ettersburg,  apple  orchard __ 

Humus  loam  ._ 

.25 

Oxnard,   sugar  beet  field    -    .  _  __ 

Fertile   sandv   loam 

.10 

Fertile  gravelly  loam    . 

09 

Santa  Paula,   citrus  orchard __ 

Fertile  gravelly  loam _      

.08 

Santa  Paula,  citrus  orchard 

Fertile  gravelly  loam__ 

.08 

Santa  Paula,  citrus  orchard 

Fertile  gravelly  loam 

.07 

Riverside,   citrus   orchard 

Poor  silty  sand    

.05 

The  variety  of  locations  representing  twenty  counties  in  the  state 
from  which  the  soils  described  in  the  foregoing  table  were  derived,  is  a 
large  one,  and  gave  opportunity  of  obtaining  not  only  a  great  diversity 
as  regards  "lightness"  or  "heaviness,"  but  also  of  insuring  even 
greater  variations  in  chemical  and  biological  composition.     This  is  so 


18996- 


110 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 


because  of  their  formation  under  climatic  conditions,  the  variety  of 
when  need  here  only  be  attested  to  by  the  great  range  in  but  one  phase 
thereof,  namely  the  rainfall.  The  normal  rainfall  received  by  the 
Imperial  Valley  soil  for  example,  is  about  one  and  one-half  to  two 
inches  per  year,  while  that  for  the  Mattole  River  soil  from  Ettersburg, 
Humboldt  County,  is  about  sixty  inches.  Many  variations  are  found 
in  between  these  extremes.  It  follows  necessarily  that  difference  in 
soils  due  to  such  climatic  variations  must  perforce  be  accompanied  by 
differences  in  organic  matter  content  of  the  same  soils  and  that  has 
been  found  to  be  the  case. 

The  fertilizers  employed  included  a  variety  of  the  common  organic 
nitrogenous  fertilizers  and  with  them  two  inorganic  materials— sulphate 
of  ammonia  and  calcium  cyanamid — the  first  a  by-product  of  gas  and 
coke  manufacture  and  the  second  one  produced  by  electrical  processes 
employed  for  combining  the  nitrogen  of  the  air  with  lime.  A  full  list 
of  the  materials  employed  along  with  their  percentage  composition  as 
regards  total  nitrogen  and  nitrate  nitrogen  are  given  in  the  following 
table : 

TABLE  II. 

Description  and  Partial  Cora  position  of  Fertilizers  Employed  in  the  Experiment. 


Number 


Total  N 
per  cent 


Mgs. 

nitrate  N 

per  gram 

of  material 


1  Dried  blood   12.29  .C8 

2  High    grade    tankage 9.25  .CO 

3  Steamed  bone  meal 3.C3  1.00 

4  Fish    guano    8.47  .CO 

5  Cottonseed    meal    5. 50\  .CO 

6  Calcium  cyanamid  16.55  .05 

7  Sulfate   of    ammonia 21. CO  .CO 

8  Goat    manure    2.46  2.50 

9  Garbage  tankage  2.2  to  2.3  .00 

10  Apple   pomace    .00 

11  Barnyard   manure   1.40  Trace 

12  Green    alfalfa    4. CO  .CO 

13  Green  kelp  (Macrocystis)         1.40  .CO 

14  Sewage  sludge.* 
[ \ 

fSee  Bull.  251,  Cal.  Agr.  Expt.  Station. 


!  As  found  on  market  for  fertilizer. 

As  found  on  market  for  fertilizer. 
j  17%  P2O5;    as  on  market. 

As  on  market. 

As  on  market. 

As  on  market. 

Baker's  c.p. 
I  As  on  market. 

As  on  market. 

Obtained   from   Hood   River  Valley. 

Well  rotted  condition. 

Freshly  cut. 

Freshly     gathered      and      contained 
18.7%  chlorides. 


The  nitrate  determinations  were  made  in  accordance  with  the  usual 
quantitative  chlorimetric  methods  at  the  end  of  the  incubation  period. 
The  amounts  obtained  in  the  case  of  every  soil  and  of  every  fertilizer  as 
indicating  the  degree  of  nitrification  in  all  combinations  are  shown  to 
best  advantage  in  the  following  tables. 


/ 


Bulletin  260] 


NITROGENOUS   FERTILIZERS. 


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NITROGENOUS    FERTILIZERS. 


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114  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

It  is  at  once  evident  from  an  examination  of  the  foregoing  tables  that 
there  is  a  wide  variation  in  the  power  of  different  soils  to  nitrify,  under 
laboratory  conditions,  different  kinds  of  organic  nitrogen,  both  with 
regard  to  absolute  and  relative  amounts  of  nitrate  produced.  Beyond 
this  general  observation  it  is  difficult  to  analyze  the  significance  of  the 
tables  without  considering  every  nitrogenous  material  separately.  We 
shall  therefore  take  them  up  for  discussion  one  by  one. 

Dried    Blood. 

It  is  plain  from  the  data  above  submitted  with  respect  to  the  nitrifia- 
bility  of  dried  blood  that  the  latter,  so  far  as  arid  soils  are  concerned, 
can  not  be  regarded  as  a  "high  grade"  material,  if  availability  is  the 
criterion  of  quality.  This  is,  of  course,  contrary  to  the  common  teach- 
ing with  regard  to  that  material.  To  be  sure  there  are  some  soils  in 
which  dried  blood  has  shown  a  relatively  good  availability.  These  soils, 
however,  are  not  only  in  the  minority,  but  in  addition  do  not  show  dried 
blood  nitrogen  to  be  exceptionally  available  in  any  case. 

Of  twenty-nine  soils  tested  with  dried  blood,  eleven,  or  nearly  38%, 
transformed  less  than  1%  of  the  total  nitrogen  present  in  one  gram  of 
dried  blood  (122  mgs.  N)  into  nitrate  in  a  month's  incuhation  period  at 
nearly  optimum  moisture  and  temperature  conditions.  This  is  signifi- 
cant not  only  because  of  the  small  percentage  of  the  total  nitrogen  in 
the  blood  added,  which  was  changed  to  nitrate,  but  because  of  the  very 
small  absolute  amount  of  nitrate  which  is  produced.  It  must  be  further 
noted  that  in  many  cases,  of  the  38%  of  soils  which  transformed  less 
than  1%  of  the  blood  nitrogen  into  nitrate,  there  was  not  only  no 
nitrate  produced,  but  an  actual  loss  thereof  from  the  amount  originally 
present  in  the  soil,  was  occasioned.  Of  the  62%  which  make  up  the 
balance  of  the  soils  tested  with  dried  blood,  six,  or  a  little  over  20% 
of  the  total  number,  transformed  between  1%  and  5%  of  the  total  nitro- 
gen present  in  the  dried  blood  into  nitrate.  Three  soils,  or  a  little 
over  10%,  transformed  more  than  five  and  less  than  10%  of  the  total 
nitrogen  into  nitrate.  Of  the  balance,  four  soils  transformed  more 
than  10%  and  less  than  20%  of  the  nitrogen  into  nitrate,  four  soils 
which  changed  more  than  20%  and  less  than  25%  and  only  one  soil 
which  transformed  more  than  25%  of  the  total  nitrogen  in  dried  blood 
into  nitrate  and  that  was  only  slightly  more. 

We  thus  see  that  about  68%  of  all  the  soils  tested  are  incapable  of 
rendering  available  more  than  one-tenth  of  the  total  nitrogen  in  the 
dried  blood,  and  that  most  of  them  are  far  below  even  the  10%  mark. 
Moreover,  there  are  nearly  14%  more  of  the  total  number  of  soils  which 
fall  below  the  limit  of  power  to  render  into  nitrate  one-fifth  of  the 
total  amount  of  nitrogen  present,  leaving  only  about  18%  of  the  total 
number  of  soils  which  can  transform  more  than  one-fifth  of  the  total 


[Bulletin  260]  nitrogenous  fertilizers.  115 

nitrogen  present  into  nitrate.  As  noted  above,  in  the  last  group  of 
soils,  the  nitrifying  power  exceeds  the  20%  limit  by  very  little,  only 
one  soil  rising  above  the  25%  limit  and  that  but  slightly. 

The  five  soils  capable  of  transforming  more  than  one-fifth  of  the 
total  nitrogen  of  the  dried  blood  into  nitrate  were :  Sacramento  River 
alluvium,  Ferndale  alluvium,  Castroville  silt,  Oxnard  sandy  silt,  and 
Santa  Paula  loam  (lower  section  2,  Teague-McKevitt  Ranch).  It  is 
significant  that  all  of  these  soils  are  well  supplied  with  organic  matter, 
and  further  that  only  two  of  the  soils  which  were  well  supplied  with 
organic  matter  did  not  stand  out  as  good  nitrifiers  of  blood  nitrogen 
when  compared  with  the  other  soils. 

"High    Grade"  Tankage. 

"With  one  or  two  notable  exceptions  the  soils  under  consideration  here 
behave  with  respect  to  tankage  nitrogen  in  much  the  same  fashion  as 
they  do  with  respect  to  dried  blood  nitrogen.  At  least,  the  values  for 
nitrogen  transformation  in  tankage  are  of  about  the  same  order  of 
magnitude  as  those  for  the  nitrogen  transformation  in  blood  in  most  of 
the  soils.  Of  the  exceptions  just  noted  the  only  really  striking  one  is 
that  in  Soil  No.  4,  in  which  over  27%  of  the  nitrogen  of  the  tankage 
added  was  changed  to  nitrate,  whereas  less  than  1.5%  of  the  nitrogen  of 
the  blood  was  so  changed  in  the  same  soil.  Here,  however,  it  must  be 
noted  that  we  are  dealing  with  one  of  the  two  exceptional  soils  men- 
tioned at  the  end  of  the  foregoing  paragraph  and  in  this  case  it  is  no 
exception  to  the  general  rule.  Arranging  the  soils  in  the  order  of  their 
efficiency  with  respect  to  the  nitrification  of  tankage  nitrogen  we  obtain 
the  following  statement : 

1.  Five  soils,  or  a  little  over  17%  of  the  total  number,  either  produce 
no  nitrate  or  induce  a  loss  of  the  soil's  nitrate. 

2.  Ten  soils,  or  nearly  35%  of  the  total  number  transform  in  every 
case  less  than  5%  of  the  total  nitrogen  in  tankage  into  nitrate.  In  a 
number  of  cases  much  less  than  5%  is  thus  transformed. 

Adding  these  first  two  classes  together,  we  find  that  about  52%  of 
the  soils  are  below  the  5%  limit  in  the  case  of  tankage  as  against  58% 
in  the  case  of  dried  blood,  which  indicates  a  strong  parallelism  between 
the  two  materials. 

3.  The  soils  falling  between  the  5%  and  10%  limits  in  the  case  of 
tankage  are  four  in  number,  or  about  14%  of  the  total. 

4.  Of  the  balance,  five  fall  between  the  10%  and  20%  limits,  two 
between  the  20%  and  25%  limits,  and  three  above  the  25%  limit. 

In  general,  therefore,  there  is  a  marked  similarity  between  the  nitro- 
gen of  dried  blood  and  that  of  tankage  from  the  point  of  view  of  their 
nitrifiability.  Thus  in  the  case  of  tankage,  72%  of  the  soils,  as  against 
68%  in  the  case  of  the  dried  blood,  are  in  the  class  which  transform  less 


116  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

than  one-tenth  of  the  total  nitrogen  present  into  nitrate.  This  slight 
superiority  of  the  blood  is,  however,  more  than  counterbalanced  by  a 
higher  percentage  in  the  case  of  the  tankage  above  the  25%  limit  and 
by  the  fact  that  the  maximum  transformation  of  organic  nitrogen  into 
nitrate  in  the  case  of  tankage,  is  much  greater  than  in  the  case  of 
dried  blood.  Again  the  Salinas  soil  stands  among  the  best  nitrifiers  of 
organic  nitrogen  of  the  type  of  that  in  dried  blood  and  tankage.  In 
brief,  it  appears  from  an  examination  of  the  data  given  for  both  dried 
blood  and  tankage  that  the  latter  is  superior  to  the  former  from  the 
point  of  view  of  the  nitrifiability  of  its  nitrogen,  but  that  both  forms 
are  but  poorly  adapted  to  arid  soils  considered  by  and  large. 

Steamed    Bone   Meal  or  "Low  Grade"  Tankage. 

Strikingly  different  from  the  two  materials  just  discussed  is  steamed 
bone  meal  from  the  point  of  view  of  the  nitrifiability  of  its  nitrogen. 
Not  only  is  the  latter  more  economically  changed  to  nitrate  and  in 
larger  quantity,  but  it  seems  to  be  much  better  suited  to  the  nitrifying 
processes  in  California  soils  as  a  whole.  We  may  briefly  summarize 
the  data  bearing  on  steamed  bone  meal  in  the  tables,  as  follows : 

1.  In  two  soils  only  does  the  steamed  bone  meal  nitrogen  remain 
unnitrified,  and  only  in  one  of  these  a  loss  of  nitrate  from  the  original 
soil  is  obtained.  In  the  first  of  these,  the  Selma  sand,  the  nitrifying 
power  is  extremely  feeble,  no  matter  what  form  of  nitrogen  is  added. 
In  the  second  soil  so  much  nitrate  is  originally  present  from  heavy 
nitrate  applications  as  to  discourage  nitrification  of  all  forms  of  nitro- 
gen except  those  of  cottonseed  meal  and  sulfate  of  ammonia. 

2.  Only  three  soils  besides  the  two  just  discussed,  or  about  10%  of 
the  whole  number  employed,  transform  less  than  5%  of  the  total  nitro- 
gen in  steamed  bone  meal  into  nitrate. 

Taking  the  soils  under  paragraphs  1  and  2  together,  we  find  that 
only  17%  of  the  total  number  of  soils  fall  below  the  5%  limit,  as  against 
52%  in  the  case  of  the  tankage,  and  58%  in  the  case  of  the  dried  blood. 

3.  Only  two  soils  fall  between  the  5%  and  10%  limits  with  regard  to 
the  nitrogen  in  steamed  bone  meal,  and  only  two  more  between  the  10% 
and  20%  limits. 

4.  Nine  soils  fall  in  the  group  between  20%  and  30%  limits,  four 
soils  between  the  30%  and  40%  limits,  four  soils  between  the  40%  and 
50%  limits,  and  three  soils  between  the  60%  and  70%  limits. 

The  reversal  of  conditions  between  the  steamed  bone  meal  nitrogen 
and  that  of  the  two  "high  grade"  materials  previously  discussed  is 
most  striking.  Thus  we  find  that  whereas  P0%  to  90%  of  the  soils 
tested  have  too  low  a  nitrifying  power  for  blood  and  tankage  nitrogen 
to  transform  20%  of  it  into  nitrate,  about  70%  of  the  same  soils  can  do 
better  than  to  transform  20%  of  the  total  nitrogen  of  steamed  bone 


[Bulletin  260]  nitrogenous  fertilizers.  117 

meal  into  nitrate.  No  less  striking  than  this  is  the  fact  that  while  only 
one  soil  of  the  twenty-nine  used  is  capable  of  transforming  more  than 
one-fourth  of  the  total  nitrogen  in  blood  into  nitrate  and  only  three  of 
doing  so  in  the  case  of  tankage,  there  are  eleven  which  can  transform 
more  than  one-third  of  the  total  nitrogen  of  the  steamed  bone  meal  in 
that  manner.  The  maximum  point  of  economical  transformation  of 
nitrogen  into  nitrate  is  above  66%  of  the  total  nitrogen  present  in  the 
case  of  steamed  bone  meal  nitrogen  while  it  is  only  half  that  in  the  case 
of  ' '  high  grade ' '  tankage  and  much  less  than  half  that  figure  in  the  case 
of  the  dried  blood. 

Fish   Guano. 

Only  twenty-four  soils  were  included  in  the  fish  guano  series.  Fish 
guano  seems  to  be  noticeably  better  adapted  to  nitrification  than  dried 
blood  and  tankage.  This  is  at  least  true  in  a  number  of  soils.  In 
general,  however,  values  obtained  for  the  nitrifiability  of  the  fish  guano 
nitrogen  resemble  more  those  of  the  blcod  and  tankage  than  those  of 
the  steamed  bone  meal  and  are  of  about  the  same  order  of  magnitude. 
Summarizing  the  data  for  fish  guano  as  in  the  foregoing  cases,  we  find 
the  following  to  be  true : 

1.  Four  soils  or  nearly  17%  of  the  total  number  tested  produce  no 
nitrate  from  fish  guano  or  induce  losses  of  the  nitrate  originally  present 
in  the  culture. 

2.  Five  soils,  or  nearly  21%  of  the  total  number  tested,  transform 
less  than  5%  of  the  nitrogen  present  in  the  fish  guano  into  nitrate. 

3.  Five  soils,  or  about  21%  of  the  total  number  tested,  transform 
more  than  five  or  less  than  10%  of  the  nitrogen  in  fish  guano  into 
nitrate  under  the  conditions  mentioned. 

4.  Of  the  balance,  six  soils  fall  between  the  10%  and  20%  limits,  two 
between  the  20%  and  25%  limits,  and  two  above  the  25%  limit. 

It  is  obvious,  therefore,  that  the  greatest  difference  between  high 
grade  tankage  and  fish  guano  is  that  there  is  a  much  smaller  number 
of  soils  showing  an  availability  with  the  latter  fertilizer  which  falls 
below  the  5%  limit  of  nitrogen  transformation  than  is  the  case  with 
the  first  named  fertilizer.  This  necessarily  increases  the  number  of 
soils  in  the  5%  to  10%  class,  and  in  the  10%  to  20%  class  with  respect 
to  fish  guano,  but  it  does  not  otherwise  affect  very  seriously  the  absolute 
coefficient  of  nitrifiability  of  the  fish  guano.  Beyond  the  25%  limit 
the  latter  exhibits  characteristics  very  much  like  those  of  the  high  grade 
tankage.  From  the  relative  standpoint,  however,  as  was  intimated 
above,  fish  guano  is  superior  to  both  dried  blood  and  high  grade  tankage 
in  its  nitrifiability.  Thus  for  example,  about  one-half  of  the  soils  in 
the  case  of  high  grade  tankage  transform  less  than  5%  of  the  total 
nitrogen  into  nitrate,  whereas  the  corresponding  half  of  the  soils  in  the 


118  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION. 

case  of  the  fish  guano  fall  below  the  10%  limit.  As  between  dried 
blood,  high  grade  tankage  and  fish  guano  therefore,  the  first  place  must 
be  accorded  the  last  named,  the  second  place  to  tankage,  and  the  third 
place  to  dried  blood  from  the  point  of  view  of  nitrifiability  of  the  nitro- 
gen in  arid  soils. 

Here  again  it  must  be  added  that  the  humus-rich  soils  plainly  show 
their  superiority  to  the  others  in  rendering  nitrogen  available  in  the 
high  grade  nitrogenous  fertilizers.  Also,  as  in  the  case  of  the  tankage 
and  dried  blood,  over  80%  of  the  soils  tested  with  fish  guano  nitrogen 
were  found  incapable  of  transforming  more  than  20%  of  it  into 
nitrate. 

Cottonseed    Meal. 

The  marked  superiority  of  the  low  grade  over  the  high  grade  nitro- 
genous material  in  humus-poor  soils  which  our  investigations  have 
demonstrated  is  nowhere  more  strikingly  exemplified  than  in  the  figures 
for  the  nitrifiability  of  the  nitrogen  in  cottonseed  meal  as  given  in  the 
foregoing  tables.  Cottonseed  meal  clearly  is  to  be  classified  with 
steamed  bone  meal  in  that  respect  but  is  superior  even  to  the  last 
named  material,  the  good  qualities  of  which  are  discussed  above. 
Employing  again  the  statistical  method  of  summarizing  the  results 
obtained  in  the  experiment  the  following  statement  may  be  made. 

1.  Not  one  soil  of  the  twenty-nine  tested  showed  a  total  lack  of 
power  to  nitrify  cottonseed  meal  nitrogen,  though  it  must  be  conceded 
that  in  one  case  (Soil  No.  11)  only  traces  of  nitrate  were  found  in 
excess  of  the  quantity  originally  present  in  the  soil. 

2.  Six  soils,  or  nearly  21%  of  the  total  number  tested  were  found 
capable  of  transforming  5%  or  less  of  the  total  nitrogen  of  cottonseed 
meal  into  nitrate. 

3.  Only  one  soil,  or  less  than  3.5%  of  the  total  number  of  soils  tested, 
transformed  more  than  5%  and  less  than  10%  of  the  cottonseed  meal 
nitrogen  into  nitrate. 

4.  Five  soils,  or  about  17%  of  the  total  number  of  soils  tested,  trans- 
formed between  10%  and  20%  of  the  nitrogen  in  cottonseed  meal  into 
nitrate. 

5.  Twelve  soils,  or  over  41%  of  the  total  number  tested  are  capable 
of  transforming  from  20%  to  30%  of  the  total  nitrogen  in  cottonseed 
meal  into  nitrate. 

6.  Three  soils,  or  over  10%  of  the  total  number  fall  between  the  30% 
and  40%  limits  in  regard  to  nitrifiability  of  cottonseed  meal  nitrogen. 

7.  One  soil  transforms  nearly  45%  of  the  nitrogen  in  cottonseed  meal 
into  nitrate. 

It  is  clear  from  the  foregoing  data  that  less  than  25%  of  the  total 
number  of  soils  tested  falls  below  the  10%  limit  with  cottonseed  meal 
nitrogen,  and  only  a  little  over  40%  fall  below  the  20%  limit.     "We  thus 


[Bulletin  260]  nitrogenous  fertilizers.  119 

have  again  a  similarity  between  steamed  bone  meal  nitrogen  and  cotton- 
seed meal  nitrogen  in  that  about  60%  or  more  of  the  soils  in  both  cases 
transform  more  than  20%  of  the  nitrogen  into  nitrate.  In  this  respect 
the  steamed  bone  meal  is  slightly  superior  to  the  cottonseed  meal,  as  it 
is  also  in  the  case  of  the  efficiency  of  the  best  nitrifying  soil.  The 
latter,  No.  21,  transformed  over  66%  of  the  nitrogen  of  steamed  bone 
meal  into  nitrate,  whereas  it  changed  only  a  little  over  44%  of  the 
nitrogen  in  the  cottonseed  meal  into  that  form. 

Calcium   Cyanamid. 

The  results  obtained  by  us  with  calcium  cyanamid  sometimes  known 
as  lime  nitrogen,  are  not  capable  of  discussion  like  the  others  set  forth 
in  this  bulletin.  Calcium  cyanamid,  or  "lime  nitrogen"  is  a  "high 
grade"  nitrogenous  fertilizer  and  has  only  recently  been  produced  on 
a  commercial  scale.  The  product  used  by  us  came  from  one  of  the 
European  cyanamid  plants  and  contained  about  16%  nitrogen  and  an 
excess  of  caustic  lime.  It  was  in  many  respects  similar  to  other  forms 
of  lime  nitrogen  on  the  market,  but  different,  for  example,  from  the 
product  of  the  Niagara  Falls  plant  in  that  the  latter  contains  no  excess 
of  lime.  The  experiments  in  which  lime  nitrogen  has  been  tested  by 
investigators  in  all  parts  of  the  world  and  in  every  conceivable  manner 
are  numerous  and  the  literature  on  the  subject  is  very  voluminous. 
So  far  as  we  are  aware,  however,  most  of  the  experiments  in  which  the 
calcium  cyanamid  was  used  in  soil  were  carried  out  in  humid  regions 
in  which  organic  matter  is  characteristically  present  in  much  larger 
quantities  than  in  arid  soils.  In  general,  these  investigations  have 
not  resulted  in  a  definite  appraisal,  even  under  humid  soil  conditions, 
of  the  place  and  value  of  calcium  cyanamid  among  our  nitrogen 
fertilizers.  At  least  they  have  produced  so  much  diagreement  in 
opinion  as  to  give  us  no  guide  at  present  in  the  use  of  the  fertilizer 
in  question.  Some  have  reported  very  good  results  with  various  crops 
when  calcium  cyanamid  was  used  as  a  fertilizer  and  showed  a  very 
favorable  comparison  thereof  with  nitrate  of  soda  and  sulfate  of 
ammonia.  Others  obtained  diametrically  opposite  results  and  claim 
to  have  noted  injurious  effects  of  the  calcium  cyanamid  to  the  crop 
and  to  the  soil  bacteria.  To  make  matters  more  confusing  for  the 
student  of  the  subject  there  is  very  frequently  no  similarity  in  the 
material  employed  by  different  investigators,  no  similarity  in  amount 
used,  and  a  great  divergence  of  soils,  media,  analytical  methods  and 
in  many  other  important  determinants  of  results. 

The  results  obtained  by  us  as  given  in  Table  III  would  seem  to  indi- 
cate that  our  soils  without  exception  are  not  only  incapable  of  nitrify- 
ing the  nitrogen  in  calcium  cyanamid,  but  also  that  the  latter  induces 
losses  of  nitrates  from  the  soil's  original  content  thereof  during  one 


120 


UNIVERSITY   OF    CALIFORNIA EXPERIMENT    STATION. 


month's  incubation  period.  In  a  manner  these  results  are  similar  to 
those  obtained  by  de  Grazia,  Miintz  and  Nottin,  and  several  other 
European  investigators.  The  experimenters  named  here,  however, 
noted  that  when  much  longer  incubation  periods  are  allowed,  the  cyana- 
mid  nitrogen  finally  becomes  transformed  into  nitrate  almost  com- 
pletely. Thinking,  also,  that  the  amounts  of  calcium  cyanamid 
employed  by  us  were  probably  far  too  large,  we  repeated  the  experiment 
with  three  typical  soils  and  employed  instead  of  1%  of  calcium  cyanamid 
throughout,  varying  quantities  as  shown  below.  In  a  month's  period 
of  incubation,  however,  the  smaller  amounts  of  calcium  cyanamid  in  all 
soils  but  one  acted  like  the  larger  amounts.  In  one  case,  that  of  the 
Davis  clay  loam  soil,  with  the  smallest  amount  of  the  fertilizer  used,  fair 
nitrification  was  obtained.  We  realize,  of  course,  that  even  the  smallest 
amount  of  calcium  cyanamid  employed  by  us  was  probably  ten  times 
or  more  the  quantity  that  would  be  employed  in  field  practice;  never- 
theless, twice  the  quantity  of  sulfate  of  ammonia  employed  by  us  as 
above  has  yielded  excellent  results. 

TABLE  IV. 

Showing  Effect  of  Varying  Quantities  and  Different  Soils  on  Nitrification  of  Calcium 

Cyanamid  Nitrogen. 


Davis  clay  loam 

Anaheim  sand 

Oakley  sand 

Amount  CaCXs  used,  per  cent 

Mgs.  N 
nitrified 

Per  cent 
total  N 
nitrified 

Mgs.  N 
nitrified 

Per  cent 
total  N 
nitrified 

Mgs.  N 
nitrified 

Per  cent 
total  N 
nitrified 

.10    

4.85 

.05 

-.15 

—.15 

| 
29.30                .18 
Trace               14 
.04 

.Cfl 

1.C9                .00 
Trace          — .10 
Trace          —.10 

—.10 

.25    ___        

.50    

.75    ._ 

In  view  of  the  foregoing  table,  no  recommendations  are  made  and  no 
appraisal  given  by  us  of  calcium  cyanamid  as  a  fertilizer  for  arid  soils 
with  the  following  exception.  We  believe  it  safer  for  the  present,  in 
view  of  our  results  and  those  of  others,  to  fall  back  on  the  use  of 
nitrogenous  fertilizers  whose  nature  and  effects  are  better  known  than 
to  employ  calcium  cyanamid  which  we  have  not  studied  thoroughly 
enough  to  understand  its  action.  The  fact  that  even  in  relatively 
small  quantities  only  the  Davis  soil  of  the  three  tested  can  nitrify  the 
nitrogen  of  calcium  cyanamid  seems  to  indicate  again,  as  found  by 
many  other  experimenters,  that  a  sufficient  quantity  of  organic  matter 
may  neutralize  the  poisonous  effects  of  the  fertilizer  under  considera- 
tion. In  common  with  Abey,  a  European  investigator,  the  writers 
have  noted  the  marked  production  of  acetylene  gas  in  their  soil  cultures 
with  calcium  cyanamid,  and  believe  that  that  may  produce  either  the 
temporary  or  permanent  retarding  effects  on  the  nitrification  of  lime 
nitrogen  which  has  been  variously  noted,  as  above  explained. 


[Bulletin  260]  nitrogenous  fertilizers.  121 

Sulfate  of  Ammonia. 

Sulfate  of  ammonia  is  the  second  of  but  two  inorganic  sources  of 
nitrogen  which  have  been  compared  in  our  work  with  the  organic 
sources  of  that  element.  The  results  obtained  with  it  as  set  forth  in 
the  foregoing  tables  place  it  clearly  in  the  same  class  with  the  low 
grade  nitrogenous  materials  above  discussed,  from  the  standpoint  of 
nitrifiability  of  its  nitrogen  in  arid  soils.  Thus  it  appears  to  be  nitrified 
to  a  degree  more  characteristic  of  steamed  bone  meal  and  cottonseed 
meal  than  of  dried  blood  and  high  grade  tankage.  Summarizing  the 
results  obtained  with  sulfate  of  ammonia,  we  find  the  following: 

1.  As  in  the  case  of  the  cottonseed  meal  not  one  soil  of  the  twenty- 
nine  tested  failed  to  nitrify  sulfate  of  ammonia  nitrogen.  Indeed,  the 
latter  form  of  nitrogen  is  superior  in  this  respect  to  that  of  cottonseed 
meal  because  in  the  case  of  one  soil  the  latter  was  only  very  slightly 
nitrified  as  above  stated,  whereas  definite  nitrification  of  sulfate  of 
ammonia  nitrogen  occurred  in  all  the  soils  here  tested  without  even  an 
apparent  -exception. 

2.  Again  as  in  the  case  of  the  cottonseed  meal,  six  soils  only  fall  into 
that  class  in  which  but  5%  or  less  of  the  total  nitrogen  present  (21% 
of  all  the  soils)  is  transformed  into  nitrate. 

3.  According  to  the  same  criteria,  however,  there  are  six  soils  in  the 
case  of  sulfate  of  ammonia,  or  again  21%  of  the  total  number,  which 
fall  between  the  5%  and  10%  limits.  This  is  in  striking  contrast  with 
both  cottonseed  meal  and  steamed  bone  meal,  the  corresponding  num- 
ber in  the  first  case  representing  only  3-|%  and  in  the  second  case  only 
7%  of  the  total  number  of  soils  tested. 

4.  Five  soils,  or  about  17%  of  the  whole  number,  transformed  be- 
tween 10%  and  20%  of  the  total  sulfate  of  ammonia  nitrogen  into 
nitrate.    The  same  is  true  of  cottonseed  meal. 

5.  Five  soils,  or  17%  of  the  whole  number  again  fall  between  the  20% 
and  30%  limits  on  the  basis  of  the  same  criteria  in  the  case  of  the 
sulfate  of  ammonia.  This  contrasts  strikingly  with  nine  soils  in  the 
case  of  the  steamed  bone  meal,  and  12  soils  in  the  case  of  the  cottonseed 
meal. 

6.  Again  five  soils,  or  17%  of  the  whole  number,  fall  between  the 
30%  and  40%  limits  in  the  case  of  sulfate  of  ammonia  based  on  the 
same  criteria  which  are  employed  for  the  other  materials.  This  is  not 
unlike  the  case  of  steamed  bone  meal  with  four  soils  in  that  category, 
though  more  unlike  cottonseed  meal  with  but  three  soils  in  that  class. 

7.  No  soils  fall  between  the  40%  and  50%  limits  in  the  case  of  sulfate 
of  ammonia,  but  two  of  them  transform  respectively  more  than  56% 
and  57%  of  the  sulfate  of  ammonia  nitrogen  into  nitrate.  This  is 
unlike  the  case  of  cottonseed  meal  in  which  but  one  soil  is  found  in  the 


122  UNIVERSITY   OF    CALIFORNIA EXPERIMENT    STATION. 

45%  class,  and  entirely  unlike  the  case  of  steamed  bone  meal  in  which 
four  soils  are  found  between  the  40%  and  50%  limits,  none  between  the 
50%o  and  60%  limits,  but  three  between  the  60%  and  70%  limits. 

In  general,  therefore,  a  study  of  the  foregoing  data  appears  to 
reverse  the  figures  for  nitrifiability  above  and  below  certain  limits  be- 
tween cottonseed  meal  and  steamed  bone  meal  on  the  one  hand,  and 
sulfate  of  ammonia  on  the  other.  Thus  in  the  cases  of  the  first  two 
materials  60%  or  more  of  the  total  number  of  soils  falls  above  the  20% 
limit  in  the  sense  in  which  this  term  is  used  throughout  this  bulletin, 
whereas  in  the  case  of  sulfate  of  ammonia,  60%  or  more  of  the  whole 
number  of  soils  fall  below  the  20%  limit.  On  the  other  hand,  sulfate 
of  ammonia  is  better  suited  to  the  soils  of  higher  efficiency  which  fall 
between  the  30%  and  40%  limits  than  the  other  two  materials  just 
compared  with  it,  and  two  soils  attain  a  maximum  efficiency  with  it 
which  they  do  not  at  all  approach  with  cottonseed  meal.  In  that 
respect,  however,  or  in  point  of  maximum  efficiency,  the  steamed  bone 
meal  still  stands  superior  to  all  other  materials  with  the  criterion 
employed  here  throughout. 

Goat   Manure.* 

The  goat  manure,  like  the  fish  guano  and  the  calcium  cyanamid,  was 
tested  in  only  24  of  the  29  soils.  It  will  be  noted  in  the  tables  that 
when  judged  by  nitrifiability,  the  goat  manure  nitrogen  cannot  be 
regarded  as  an  easily  available  source  of  nitrogen  in  most  of  our  soils. 
Because,  however,  of  the  fact  that  it  does  not  fail  altogether  to  nitrify 
in  any  soil  and  because  of  one  or  two  other  interesting  features  about 
the  results  obtained,  we  give  in  this  case  as  in  the  foregoing  a  statistical 
resume  of  the  data  obtained  as  folloAvs : 

1.  In  no  soil  of  the  twenty-four  tested  does  the  goat  manure  nitrogen 
fail  entirely  to  nitrify. 

2.  In  twelve  soils,  or  in  50%  of  the  total  number  tested,  less  than 
5%  of  the  total  nitrogen  added  in  the  goat  manure  is  transformed  into 
the  nitrate  form. 

3.  Nine  soils,  or  37%  of  the  total  number  tested  permit  of  the  trans- 
formation of  from  5%  to  10%  only  of  the  total  nitrogen  added  in  the 
goat  manure. 

4.  Two  soils,  or  a  little  over  8%  of  the  total  number  transform, 
respectively,  about  11%  and  12%  of  the  total  nitrogen  in  the  goat 
manure  added  into  nitrate. 

5.  One  soil,  or  the  only  one  remaining,  attains  the  extraordinary 
record  for  this  form  of  nitrogen  of  transforming  28.65%  of  the  total 
nitrogen  of  the  goat  manure  into  nitrate. 

Regarding  as  a  whole  the  data  obtained  with  goat-manure  nitrogen 
it  is  patent  that  while  that  material  is  superior  to  blood  and  tankage 
nitrogen  in  our  humus-poor  soils,  it  is  distinctly  inferior  to  the  other 


*The    discussion    under    this    head    is    submitted    as    a    tentative    one    only.     It    is 
interesting  but  as  brought  out  in  Table  V  may  need  much  modification. 


[Bulletin  260]  nitrogenous  fertilizers.  123 

materials  in  soils  somewhat  better  supplied  with  humus.  Thus  for 
example,  while  no  soil  tested  fails  to  nitrify  goat-manure  nitrogen  to 
some  degree,  87.5%  of  the  soils  tested  fall  below  the  10%  limit  and 
nearly  96%  fall  below  the  20%  limit.  In  the  case  of  blood,  however, 
only  70%  fall  below  the  10%  limit,  and  only  about  80%  below  the 
20%  limit.  The  figures  are  somewhat  similar  for  high  grade  tankage. 
Compared  with  the  steamed  bone  meal  and  cottonseed  meal,  however, 
the  inferiority  of  the  goat  manure  is  much  more  marked  and  on  the 
whole  it  must  be  considered  a  low  grade  nitrogen  fertilizer  even  for  our 
humus-poor  soils.  It  must  be  added  here  that  an  element  of  inequality 
enters  into  the  comparison  of  goat-manure  nitrogen  with  the  other 
forms  above  considered,  owing  to  the  fact  that  twice  the  quantity  of 
the  goat  manure  was  employed  as  of  the  other  materials.  This  may 
have  caused  certain  physical  and  chemical  alterations  in  the  soil  which 
were  inimical  to  the  activity  of  the  agents  of  nitrate  formation.  This 
surmise  would  seem  to  be  well  justified  moreover,  from  the  following 
table  in  which  are  given  the  results  obtained  with  three  of  the  typical 
soils  above  used  when  only  1%  goat  manure  is  employed.  It  appears 
that  goat  manure  makes  a  very  much  better  showing  when  it  is 
employed  at  the  rate  of  1  gram  per  100  grams  of  soil,  than  when 
employed  in  twice  that  quantity.  In  fact,  the  difference  is  great 
enough  to  place  it  in  the  same  class  with  steamed  bone  meal  so  far  as 
the  Oakley  soil  is  concerned  and  with  cottonseed  meal  in  the  Davis 
soil  and  the  Anaheim  soil,  but  not  with  steamed  bone  meal  in  the  last 
named.  It  is  unfortunate  that  the  experiment  could  not,  because  of 
a  lack  of  the  original  soils,  be  repeated  with  all  the  soils.  But  the 
data  given  in  Table  V  indicates  that  the  goat  manure  should  be 
accorded  a  higher  position  as  regards  availability  of  its  nitrogen  than 
that  indicated  in  Table  III  and  in  the  discussion  based  thereon.  The 
writers  feel  that  those  who  employ  goat  manure  in  the  finely  ground 
and  dry  form  may,  in  general,  expect  nearly  as  good  results  from  it  as 
from  the  other  "low  grade"  nitrogenous  fertilizers  which  are  above 
discussed. 

TABLE  V. 

Nitrification  of  Goat  Manure  Nitrogen  1%  Goat  Manure  Employed. 


Mgs.  N 
nitrified 

Per  cent 
total  N 
nitrified 

Davis  clay  loam 

3.75 
5.60 
6.10 

15. ^5 

Oakley   sand   __  ... 

22.76 

Anaheim  sand  ._    _. _.  _                               

24  79 

124 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 


Additional    Experiments    and    Observations. 

In  addition  to  the  laboratory  experiments  above  reported,  the  writers 
have  carried  on,  for  some  time,  under  greenhouse  conditions,  tests  with 
many  of  the  same  soil  types  above  described,  in  larger  quantities  and 
employing  alfalfa,  barnyard  manure  and  kelp  nitrogen  for  the  nitrifi- 
able  material.  The  soils  were  mixed  with  the  different  materials  and 
placed  in  pots.  They  were  kept  at  nearly  optimum  moisture  conditions 
throughout  the  experiment.  Samples  were  drawn  after  three  months' 
and  after  seven  months'  incubation  and  analyzed  for  nitrate.  The 
barnyard-manure  nitrogen  and  kelp  nitrogen,  except  in  Soil  No.  15, 
not  only  gave  no  increase  of  nitrates  in  either  the  three  or  seven  months ' 
incubation  period,  but  actually  induced  considerable  loss  of  nitrate 
from  the  soil's  original  content  thereof.  Alfalfa  nitrogen,  on  the  other 
hand,  nitrified  in  all  the  soils,  though  much  better  in  some  than  in 
others. 

In  three  typical  soils,  namely  those  from  Davis,  Oakley  and  Ana- 
heim above  described,  we  had  occasion  to  test  in  addition  to  the 
materials  above  mentioned,  a  new  form  of  garbage  tankage  now  being 
produced  in  this  state,  and  also  apple  pomace,  a  waste  product  from 
the  Hood  River  Valley  in  Oregon.  The  latter  only  induced  losses  of 
nitrogen  from  the  soils  with  which  it  was  tested,  but  the  former  gave 
results  which  place  it  in  the  same  class  with  steamed  bone  meal,  cotton- 
seed meal,  sludge  from  septic  tanks,  and  goat  manure.  The  data  are 
given  in  Table  VI. 

TABLE  VI. 
Nitrification   of  Nitrogen  in    Garbage   Tankage. 


Samnle  I.                         Sample  II. 
Total  N  2.3  per  cent      Total  N  2.24  per  cent 

AI"s  N     1  Per  cent    !    Mgs   N 
nitriked       tgrtN     j  nltrfiied 

Per  cent 
total  X 
nitrified 

Davis _ 

2.15 
4.10 
4.60 

9.55  !          2.15 
20.90             4.30 
20.40             4.C0 

9.55 

Oakley __ _.  

19.10 

Anaheim    . _. 

17.70 

Just  what  place  garbage  tankage  would  take  among  these  materials 
in  different  soils  we  are  not  yet  prepared  to  say,  but  present  indications 
are  that  it  will  have  a  position  between  steamed  bone  meal  and  cotton- 
seed meal  in  our  "humus-poor"  soils. 

In  general  comment  on  the  experiments  described  above,  it  may  be 
added  here  that  all  cultures  were  run  in  duplicate  and  there  was  very 
close  checking  between  the  duplicate  determinations.  Only  averages 
are  given  above  to  save  space,  but  the  complete  data  will  be  given  by 
us  in  a  more  detailed  and  technical  publication  which  will  give  a  full 
discussion  of  many  other  features  of  our  experiments  which  are  not 


[Bulletin  260J  nitrogenous  fertilizers.  125 

cogent  here,  and  also  of  the  causes,  so  far  as  they  are  discovered  or 
surmised,  for  the  striking  results  obtained.  There  will  also  be  dis- 
cussed in  the  technical  publication  just  referred  to,  the  experiments  of 
other  investigators  on  the  same  subject  which  may  be  interesting  in 
comparison  with  ours. 

The    Use   of    Nitrogenous    Fertilizers   on    California    Soils    in    View    of   the 
Experiments  and    Results  Above   Discussed. 

It  appears  clear  to  the  writers  from  the  foregoing,  since  laboratory 
experiments  are  being  well  borne  out  by  observations  in  the  field,  that 
the  rules  employed  at  present,  for  the  use  of  nitrogenous  fertilizers  on 
our  arid  soils  and  which  we  have  borrowed  from  the  humid  regions, 
must  be  changed.  In  all  soils  of  our  interior  arid  valleys  which  are 
not  very  close  to  stream  channels  or  those  which  for  other  reasons  are 
markedly  deficient  in  organic  matter,  the  proper  bacteriological  and 
perhaps  other  conditions  do  not  obtain  to  render  into  nitrate  most 
economically  and  quickly  the  nitrogen  of  high-grade  organic  nitro- 
genous fertilizers.  On  the  other  hand,  conditions  in  those  same  soils 
are  much  more  favorable  for  the  nitrification  of  nitrogen  of  the 
low-grade  nitrogenous  fertilizers.  Similar  conditions  prevail  in  the 
"humus-poor"  soils  of  our  coast  valleys  and  of  other  valleys  in  the 
state  in  which  either  the  soils  have  always  been  deficient  in  organic 
matter  or  have  become  depleted  in  that  respect  through  excessive 
oxidation  under  favorable  climatic  conditions  assisted  by  constant 
summer  cultivation.  In  all  such  soils  therefore,  we  would  recommend 
the  use  of  fertilizers  as  follows. 

Steamed  bone  meal 1,200  lbs.  per  acre 

Cottonseed  meal 800  lbs.  per  acre 

Goat  manure 1,500  lbs.  per  acre 

Septic  or  Imhoff  tank  sludge 2,000  lbs.  per  acre 

Garbage  tankage 1,400  lbs.  per  acre 

If  an  inorganic  nitrogenous  fertilizer  is  desired,  then  sulfate  of 
ammonia  may  be  used  at  the  rate  of  250  lbs.  to  the  acre.  Nitrate  of 
soda  can  also  be  used  to  advantage  when  it  is  to  be  obtained  more 
cheaply  than  sulfate  of  ammonia,  provided  it  is  applied  before  the 
rains  or  at  least  before  the  heaviest  rains  have  fallen. 

It  becomes  necessary  at  this  point  to  consider  the  nitrate  fertilizers 
in  their  relations  with  those  discussed  above  and  in  connection  with 
their  own  intrinsic  values  for  arid  soils.  One  naturally  thinks  that 
nitrate  of  soda  or  nitrate  of  lime  should  be  the  most  desirable  of 
fertilizers  when  availability  is  the  desideratum  and  this  would  be  so 
were  it  possible  to  apply  the  nitrate  and  keep  it  in  the  root  zone  in 
the  soil.  This  is  not  so,  however,  under  our  arid  conditions  since  the 
readily  soluble  nitrates  are  quickly  brought  to  the  surface  of  the  soil 
by  capillarity,  and  as  the  water  evaporates,  are  left  behind  in  the  dry 
soil  crust  into  which  roots  do  not  enter.     Since  there  is  no  rainfall 


126  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

during  a  great  portion  of  the  year,  and  since  irrigation  water  rises 
upward  into  the  surface  six  inches  of  soil,  there  is  little  opportunity 
for  the  nitrate  of  the  crust  to  redistribute  itself  in  the  deeper  layers 
of  the  soil.  Hence  plants  may  suffer  for  want  of  nitrates  in  the  root 
zone  while  those  salts  may  be  present  in  large  quantities  in  the  dry 
surface  crust  of  the  soil.  Besides,  other  injurious  effects  of  nitrates 
following  upon  the  leaching  of  them  from  soil,  which  brings  about 
more  or  less  imperviousness,  render  it  necessary  to  employ  nitrate  (and 
in  the  latter  respect  only  nitrate  of  soda)  with  considerable  caution,  as 
observed  above.  In  general,  where  the  annual  rainfall  is  below  20  inches 
per  annum,  nitrate  should  be  employed  only  on  our  lighter  soils,  and 
the  application  should  be  made  in  the  winter  so  as  to  give  soaking 
rains  a  chance  to  distribute  it  thoroughly  in  the  deeper  soil  layers. 
On  the  heavier  soils  it  will  probably  be  best  not  to  employ  it  at  all  if 
large  quantities  must  be  applied  or  if  its  use  is  to  be  constant. 

So  far  as  soils  rich  in  organic  matter  are  concerned,  or  those  which 
are  in  the  minority  in  California  (those  well  supplied  with  organic 
matter),  the  other  organic  nitrogenous  fertilizers  may  be  used  if  an 
advantage  in  prices,  pound  for  pound  of  nitrogen,  is  likely  to  be  gained. 

Dried  blood 400  lbs.  per  acre 

High  grade  tankage 600  lbs.  per  acre 

Fish  guano 600  lbs.  per  acre 

In  cases  in  which  it  is  desirable  to  apply  more  nitrogen  in  either 
group  of  soils,  the  same  materials  may  be  employed  in  larger  quantities 
in  the  same  proportions.  Obviously,  also,  if  phosphatic  or  potash  ferti- 
lizers need  to  be  employed  with  the  nitrogenous  fertilizers,  they  can  be 
mixed  in  the  necessary  proportions  as  pointed  out  by  us  in  a  forerunner 
of  this  bulletin  (Bull.  251,  California  Agricultural  Experiment  Sta- 
tion). 

It  appears  probable  also  from  our  investigations  that  green  manuring, 
together  with  the  use  of  straw  mulches  throughout  the  summer  in  the 
case  cf  our  ' ' humus-poor ' '  soils,  will  in  time  increase  their  organic 
matter  content  to  such  a  point  as  to  enable  them  to  transform  into 
nitrate  economically  the  nitrogen  of  the  high  grade  organic  nitrogenous 
fertilizers  as  well  as  that  of  the  low  grade  materials. 

Beyond  the  considerations  above  discussed,  the  choice  of  an  individual 
nitrogenous  fertilizer  from  among  several  suitable  ones  will,  of  course, 
be  easy  of  determination  since  cost  will  be  the  chief  item  to  consider. 
The  user  of  fertilizers  will  also  find  it  convenient,  if  possible,  to  study 
Table  III  above  given  and  choose  a  fertilizer  for  his  soil  by  the  results 
obtained  by  us  with  a  soil  type  most  nearly  like  his.  We  are  indeed 
now  at  work  on  a  systematic  determination  of  the  nitrifying  powers  of 
all  California  soil  types  for  typical  fertilizer  forms  of  nitrogen  so  that 
when  the  soils  surveys  of  California  are  finally  completed  the  reports 


[Bulletin  260]  nitrogenous  fertilizers.  127 

of  them  may  also  carry  information  on  the  nitrogen  economy  of  every 
type  with  methods  for  its  maintenance  and  ready  transformation  into 
available  and  assimilable  forms. 

Summary. 

1.  Field  experiments  are  beginning  to  give  strong  evidence  that 
relative  availabilities  of  different  forms  of  nitrogen  in  fertilizers  as 
determined  by  laboratory  methods  in  nitrification  studies  are  reliable 
indices  to  the  actual  relationships  which  obtain  between  these  different 
forms  of  nitrogen  in  field  soils. 

2.  Such  studies  on  relative  availabilities  of  nitrogenous  fertilizers 
have  included  above  twenty-nine  soil  types  and  fourteen  different  forms 
of  nitrogen,  though  the  latter  were  not  always  tried  with  all  soils. 

3.  The  most  ready  and  most  economical  transformation  of  nitrogen 
into  nitrate  is  accomplished  by  soil  flora  in  our  soils  with  the  so-called 
low  grade  form  of  nitrogen  fertilizers,  like  cottonseed  meal,  steamed 
bone  meal,  goat  manure,  garbage  tankage,  and  sewage  sludge. 

4.  The  so-called  high  grade  forms  of  nitrogen  like  those  of  dried 
blood,  high  grade  tankage,  and  fish  guano  are  not  well  suited  to  most  of 
our  arid  soils ;  dried  blood  giving  the  poorest  results,  tankage  next,  and 
fish  guano  last.  Whenever  soils  contain  a  good  supply  of  organic 
material  and  the  reaction  is  alkaline,  good  results  may  be  expected  from 
these  three  materials,  however. 

5.  Sulfate  of  ammonia  is  the  most  readily  available  of  the  two  inor- 
ganic forms  of  nitrogen  tested  for  our  soils.  Indeed  it  belongs  in  the 
same  class  with  the  low  grade  nitrogenous  fertilizers  above  named,  and 
choice  between  them  must  be  based  on  financial  considerations  and  on 
the  soil's  lime  content  very  largely. 

6.  Statistical  discussions  are  given  above  which  evaluate  the  charac- 
teristics of  every  one  of  the  fertilizers  described  for  all  soil  types  used. 

7.  Recommendations  are  made  for  the  practical  application  of  the 
fertilizers  under  consideration  to  our  soils. 

8.  Many  other  important  considerations  in  the  nitrogen  fertilizer 
problem  in  arid  soils  are  discussed  above  and  a  preliminary  statement 
furnished  on  relative  values  of  barnyard  manure,  alfalfa  and  Macro- 
cystis  kelp  nitrogen. 


STATION   PUBLICATIONS   AVAILABLE   FOR  DISTRIBUTION. 


REPORTS 
1897.    Resistant   Vines,    their   Selection,    Adaptation,    and   Grafting.     Appendix   to   Viticultural 
Report  for  1896. 

1902.  Report  of  the  Agricultural  Experiment  Station  for  189S-1901. 

1903.  Report  of  the  Agricultural  Experiment  Station  for  1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-04. 

1914.  Report    of   the   College   of  Agriculture   and  the  Agricultural   Experiment  Station,    July, 

1913- June,  1914. 

1915.  Report   of   the   College   of   Agriculture   and  the   Agricultural   Experiment   Station,    July, 

191 4- June,  1915. 


BULLETINS. 


No. 

168. 


170. 
174. 
177. 

178. 
184. 

185. 


197. 


198. 
203. 

207. 
208. 
211. 

212. 
213. 

216. 


Observations    on    Some    Vine    Diseases 

in  Sonoma  County. 
Tolerance  of  the  Sugar  Beet  for  Alkali. 
Studies  in  Grasshopper  Control. 
A  New  Wine-Cooling  Machine. 
A    New    Method    of    Making    Dry    Red 

Wine. 
Mosquito  Control. 
Report    of    the    Plant    Pathologist    to 

July  1,  1906. 
Report  of   Progress   in   Cereal  Investi- 
gations. 
The  California  Grape  Root-worm. 
Grape  Culture  in  California;  Improved 

Methods      of      Wine-making;     Yeast 

from   California   Grapes. 
The  Grape  Leaf-Hopper. 
Report    of    the    Plant    Pathologist    to 

July  1,  1909. 
The  Control  of  the  Argentine  Ant. 
The  Late  Blight  of  Celery. 
How   to    Increase   the   Yield   of  Wheat 

in   California. 
California  White  Wheats. 
The  Principles  of  Wine-making. 
A     Progress     Report     upon     Soil     and 

Climatic      Factors      Influencing      the 

Composition  of  Wheat. 


No. 
220. 
225. 
227. 
230. 
234. 
241. 
242. 
244. 
246. 
248. 

249. 
250. 
251. 


252. 
253. 

254. 

255. 
256. 

257 . 
258. 
259. 
260. 


Dosage  Tables. 

Tolerance  of  Eucalyptus  for  Alkali. 

Grape  Vinegar. 

Enological  Investigations. 

Red  Spiders  and  Mites  of  Citrus  Trees. 

Vine  Pruning  in  California.     Part  I. 

Humus  in  California  Soils. 

Utilization  of  Waste  Oranges. 

Vine  Pruning  in  California.     Part  LT. 

The  Economic  Value  of  Pacific  Coast 
Kelps. 

Stock  Poisoning  Plants  of  California. 

The  Loquat. 

Utilization  of  the  Nitrogen  and  Or- 
ganic Matter  in  Septic  and  Imhoff 
Tank  Sludges. 

Deterioration  of  Lumber. 

Irrigation  and  Soil  Conditions  in  the 
Sierra  Nevada  Foothills,  California. 

The  Avocado  in  California. 

The  Citricola  Scale. 

The  Value  of  Barley  for  Cows  fed 
Alfalfa. 

New  Dosage  Tables. 

Mealy  Bugs  of  Citrus  Trees. 

Commercial  Fertilizers. 

Nitrogenous  Fertilizers. 


No. 

65.  The  California  Insecticide  Law. 

69.  The  Extermination  of  Morning-Glory. 

70.  Observations    on    the    Status    of    Corn 

Growing  in  California. 
76.  Hot  Room  Callusing. 

79.  List  of  Insecticide  Dealers. 

80.  Boys'  and  Girls'  Clubs. 

82.  The     Common     Ground     Squirrels     of 

California. 

83.  Potato  Growing  Clubs. 
87.  Alfalfa. 

91.  Disinfection  on  the  Farm. 

100.  Pruning  Frosted  Citrus  Trees. 

101.  Codling    Moth    Control    in    the    Sacra- 

mento Valley. 

106.  Directions   for   using   Anti-Hog  Cholera 

Serum. 

107.  Spraying  Walnut  Trees  for  Blight  and 

Aphis    Control. 

108.  Grape  Juice. 

109.  Community  or   Local  Extension  Work 

by  the  High  School  Agricultural  De- 
partment. 

110.  Green  Manuring  in  California. 

111.  The  Use  of  Lime  and  Gypsum  on  Cali- 

fornia Soils. 

113.  Correspondence  Courses  in  Agriculture. 

114.  Increasing  the  Duty  of  Water. 


CIRCULARS. 
No. 

115. 
117. 


118. 
119. 
121. 

122. 

124. 
125. 
123. 
127. 
128. 
129. 
130. 
131. 

132. 

133. 
134. 
135. 
136. 

137. 
138. 


Grafting  Vinifera  Vineyards. 

The  Selection  and  Cost  of  a  Small 
Pumping  Plant. 

The  County  Farm  Bureau. 

Winery  Directions. 

Some  Things  the  Prospective  Settler 
Should  Know. 

The  Management  of  Strawberry  Soils 
in  Pajaro  Valley. 

Alfalfa  Silage  for  Fattening  Steers. 

Aphids  on  Grain  and  Cantaloupes. 

Spraying  for  the  Grape  Leaf-Hopper. 

House  Fumigation. 

Insecticide  Formulas. 

The  Control  of  Citrus  Insects. 

Cabbage  Growing  in  California. 

Spraying  for  the  Control  of  the  Wal- 
nut Aphis. 

When  to  Vaccinate  against  Hog 
Cholera. 

The  County   Farm  Adviser. 

Control  of  Raisin  Insects. 

Official  Tests  of  Dairy  Cows. 

MeUlotus  Indira  as  a  Green  Manure 
Crop  in  Southern  California. 

Wood  Decay  in  Orchard  Trees. 

The  Silo  in  California  Agriculture. 


